1. Field of the Invention
The present invention relates primarily to flashlights, and in particular, to miniature hand-held flashlights which may have their batteries recharged and a recharger therefor.
2. Discussion of the Prior Art
Flashlights of varying sizes and shapes are well known in the art. In particular, certain of such known flashlights utilize two or more dry cell batteries, carried in series in a cylindrical tube serving as a handle for the flashlight, as their source of electrical energy. Typically, an electrical circuit is established from one electrode of the battery through a conductor to a switch, then through a conductor to one electrode of the lamp bulb. After passing through the filament of the lamp bulb, the electrical circuit emerges through a second electrode of the lamp bulb in electrical contact with a conductor, which in turn is in electrical contact with the flashlight housing. The flashlight housing provides an electrical conduction path to an electrical conductor, generally a spring element, in contact with the other electrode of the battery. Actuation of the switch to complete the electrical circuit enables electrical current to pass through the filament, thereby generating light which is typically focused by a reflector to form a beam of light.
The production of light from such flashlights has often been degraded by the quality of the reflector utilized and the optical characteristics of any lens interposed in the beam path. Moreover, intense light beams have often required the incorporation of as many as seven dry cell batteries in series, thus resulting in a flashlight having significant size and weight.
Efforts at improving such flashlights have primarily addressed the quality of the optical characteristics. The production of more highly reflective, well-defined reflectors, which may be incorporated within such flashlights, have been found to provide a more well-defined focus thereby enhancing the quality of the light beam produced. Additionally, several advances have been achieved in the light emitting characteristics of flashlight lamp bulbs.
Since there exists a wide variety of uses for hand-held flashlights, the development of the flashlight having a variable focus, which produces a beam of light having a variable dispersion, has been accomplished.
Also, flashlights which may have their batteries recharged with a constant current recharger are known. However, such advances have heretofore been directed to xe2x80x9cfull-sizedxe2x80x9d flashlights.
It is a primary object of the present invention to provide miniature hand-held flashlights having a recharging capability.
It is another object of the present invention to provide miniature flashlights having three dry cell batteries as a power source.
It is another object of the present invention to provide miniature flashlights having various tailcap constructions.
It is another object of the present invention to provide miniature hand-held flashlights having improved optical characteristics.
It is another object of the present invention to provide a rechargeable miniature hand-held flashlight which is capable of producing a beam of light having a variable dispersion.
It is a further object of the present invention to provide a rechargeable miniature hand-held flashlight which is capable of supporting itself vertically on a horizontal surface to serve as an xe2x80x9cambientxe2x80x9d unfocused light source.
It is another object of the present invention to provide a rechargeable miniature hand-held flashlight wherein relative motions of components that produce the variation and the dispersion of the light beam provide an electrical switch function to open and complete the electrical circuit of the flashlight.
These and other objects of the present invention, which may become obvious to those skilled in the art through the hereinafter detailed description of the invention are achieved by a miniature flashlight and battery charger comprising: a cylindrical tube containing one or more miniature dry cell batteries and preferably three M sized batteries which, when used with the charger should be suitable for charging, disposed in a series arrangement, a lamp bulb holder assembly including electrical conductors for making electrical contact between terminals of a miniature lamp suitable for use with rechargeable batteries, and the cylindrical tube and an electrode of the battery, respectively, retained in one end of the cylindrical tube adjacent the batteries, a tail cap and spring member enclosing the other end of the cylindrical tube and providing an electrical contact to another electrode of the batteries and providing for charging of the batteries within the tube, and a head assembly including a reflector, a lens, a face cap, which head assembly is rotatably mounted to the cylindrical tube such that the lamp bulb extends through a hole in the center of the reflector within the lens and a charger housing which may be electrically coupled to the tube at the tailcap. In the preferred embodiment of the present invention, the batteries are of the size commonly referred to as M batteries.
The head assembly engages threads formed on the exterior of the cylindrical tube such that rotation of a head assembly about the axis of the cylindrical tube will change the relative displacement between the lens and the lamp bulb. When the head assembly is fully rotated onto the cylindrical tube, the reflector pushes against the forward end of the lamp holder assembly causing it to shift rearward within the cylindrical tube against the urging of the spring contact at the tailcap. In this position, the electrical conductor within the lamp holder assembly which completes the electrical circuit from the lamp bulb to the cylindrical tube is not in contact with the tube. Upon rotation of the head assembly in a direction causing the head assembly to move forward with respect to the cylindrical tube, pressure on the forward surface of the lamp holder assembly from the reflector is relaxed enabling the spring contact in the tailcap to urge the batteries and the lamp holder assembly in a forward direction, which brings the electrical conductor into contact with the cylindrical tube, thereby completing the electrical circuit and causing the lamp bulb to illuminate. At this point, the lamp holder assembly engages a stop which prevents further forward motion of the lamp holder assembly with respect to the cylindrical tube. Continued rotation of the head assembly in a direction causing the head assembly to move forward relative to the cylindrical tube causes the reflector to move forward relative to the lamp bulb, thereby changing the focus of the reflector with respect to the lamp bulb, which results in varying the dispersion of the light beam admitted through the lens.
By rotating the head assembly until it disengages from the cylindrical tube, the head assembly may be placed, lens down, on a substantially horizontal surface and the tailcap and cylindrical tube may be vertically inserted therein to provide a miniature xe2x80x9ctable lampxe2x80x9d.
The flashlights of the present invention preferably include three AA size batteries or smaller, suitable for charging when the charger is used. When the battery charger feature is used, a tailcap having the features shown and described herein provides a charging circuit for the batteries without removal of the batteries from the flashlight. When a charging feature is not desired, then any one of a variety of other tailcaps may be used. For example, a tailcap having a lanyard ring construction may be used. Alternatively, a tailcap having an insert and of the construction shown in co-pending application, Ser. No. 043,086, filed on Apr. 27, 1987, entitled FLASHLIGHT, issued as U.S. Pat. No. 4,327,401, may be used. Also, tailcaps not having the lanyard ring holder feature and not having the charger feature may be used. Such tailcaps would have a smooth, contoured external appearance, as shown in FIGS. 7 and 10 of the drawings. Furthermore, a tailcap having a lanyard ring feature as well as a charging feature may be used with the flashlights of the present invention, although a tailcap not having a lanyard ring is preferred when using the charging feature.
The charger for the flashlights of the present invention includes a housing, a circuit adapted to receive electrical power within a certain voltage range and to provide constant current at a predetermined rate to the batteries, and positive and negative contacts for contacting with positive and negative charging regions on the tailcap, which in turn and together with the electrical circuit of the flashlight provide for a charging circuit to the batteries. The charger may be adapted to convert AC to DC, and may be adapted to provide for various charging rates. The charger and the tailcap also contain a blocking diode to prevent a reverse charging condition to occur.